Conventionally, there have been cases where a stent, which is formed in the shape of a hollow cylinder having a multiplicity of openings in its side wall from a metallic wire or the like to be expanded in a lumen of a living body, such as a blood vessel, bile duct, trachea, esophagus and urethra, is used for improvement of a stenosed part or an obstructed part generated in the lumen of the living body.
In connection with the case of a self-expandable stent in which the stent itself has a self-expanding function, for example, there has been known a stent delivery system in which the stent is delivered into a living body in the state of being compressed and contained in a gap between an inner tube and an outer tube, and then the outer tube is retracted proximally so as to release the stent, whereby the stent is put indwelling in a desired lumen.
In Pamphlet of International Publication No. 2011/122444, a stent delivery system with this type of stent is proposed. The stent delivery system is provided with an operating unit by which an outer tube is advanced and retracted relative to an inner tube and releases the stent by moving the outer tube through the rack member meshed with a gear of a roller by the operator rotating the roller of the operating unit.